From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Wed, 6 Jul 2022 23:39:58 +0000 (-0700)
Subject: tcp: Fix a data-race around sysctl_tcp_max_orphans.
X-Git-Tag: baikal/mips/sdk6.1~5324^2~27^2~5
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=be0127d383b30c105e320dbdfa551209ef7c7010;p=kernel.git

tcp: Fix a data-race around sysctl_tcp_max_orphans.

While reading sysctl_tcp_max_orphans, it can be changed concurrently.
So, we need to add READ_ONCE() to avoid a data-race.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 028513d3e2a2b..2222dfdde3168 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2715,7 +2715,8 @@ static void tcp_orphan_update(struct timer_list *unused)
 
 static bool tcp_too_many_orphans(int shift)
 {
-	return READ_ONCE(tcp_orphan_cache) << shift > sysctl_tcp_max_orphans;
+	return READ_ONCE(tcp_orphan_cache) << shift >
+		READ_ONCE(sysctl_tcp_max_orphans);
 }
 
 bool tcp_check_oom(struct sock *sk, int shift)